Protective breathing apparatus inhalation duct

摘要

An improved protective breathing apparatus having a vent hole or one way valve incorporated into the inhalation duct so that the breathing apparatus can safely vent and release a pressure differential during the opening of the storage bag from vacuum storage. The use of an air pressure relief mechanism prevents the rupture of the duct and preserves the integrity of the device.

主权项

1. A self-contained breathing apparatus for providing emergency oxygen and adapted for storage in a vacuum-sealed condition until use, comprising:
(a) a transparent flexible hood adapted to cover the head of the wearer, including an annular seal carried by one end of the hood for sealing the hood around the neck of the wearer during use; (b) an oxygen-generating canister positioned in the hood, including a starter for initiating a oxygen-producing chemical reaction upon manual activation; (c) an oronasal mask connected in a pneumatic circuit by an inhalation duct and an exhalation duct to the canister for delivering oxygen to the wearer and returning exhaled gases to the canister; and (d) a port positioned in the inhalation duct between the canister and the mask inside the hood for allowing entry into the inhalation duct of air exterior to the hood when air pressure exterior to the hood is greater than the air pressure inside the hood prior to use.